Tonight's a movie night

IMDb

Use a computer and sign in first. IMDb can't export from the phone app or the mobile site.

1. Open your ratings, click the ⋮ button above the list, then Export. You get ratings.csv.
2. Open your watchlist, then Export: the ⋮ button at the top, or Export this list at the very bottom of the page. You get watchlist.csv.

IMDb may take a minute to prepare each file. Both land in Downloads, so you can drag them straight onto the box above.

Letterboxd

1. Open Settings → Data and click Export Your Data.
2. Unzip the download, then use ratings.csv and watchlist.csv from inside it.

Mixing is fine. IMDb ratings with a Letterboxd watchlist works.

Netflix optional

1. History, instantly. Open your viewing activity and click Download all at the bottom. You get NetflixViewingHistory.csv straight away.
2. My List, the slow way. Netflix only puts your watchlist in the full privacy export. Request it from Download your personal information, then take MyList.csv and ViewingActivity.csv out of CONTENT_INTERACTION in the zip. Netflix says this can take up to 30 days, and the download link lasts 7.

Netflix has no ratings worth exporting, having dropped stars for thumbs in 2017. So MyList.csv is treated as a watchlist like any other, while the viewing history does two jobs: films you've already watched drop out of the running, and what you've been putting on lately becomes a weaker second signal alongside your ratings. With both files, Netflix works on its own.